1. Field of the Invention
The present invention relates to an inverter device and an air conditioner including the inverter device.
2. Description of the Related Art
In the past, for example, International Patent Publication No. 2000-072433 discloses a technology for realizing a reduction in an energization loss of an entire switching circuit by configuring, as a switching circuit included in an inverter device, a parallel circuit in which a Si transistor and a non-Si transistor including a SiC or GaN semiconductor are connected in parallel and for realizing a reduction in a switching loss by simultaneously raising a gate voltage of the Si transistor and a gate voltage of the non-Si transistor.
Further, for example, International Patent Publication No. 2001-020757 discloses a technology for reducing a conduction loss and a switching loss by connecting in parallel a main transistor including a current-driven semiconductor switching element having a small conduction loss and an auxiliary transistor including a voltage-driven semiconductor element having switching speed higher than that of the current-driven semiconductor switching element to configure a main switch and turning on the auxiliary transistor earlier than the main transistor and turning off the auxiliary transistor later than the main transistor.
However, in the technology disclosed in International Patent Publication No. 2000-072433, the switching circuit is turned on by the non-Si transistor including the SiC or GaN semiconductor element having high switching speed during turn-on. Therefore, the non-Si transistor having a large current capacity needs to be used. As a result, the price of the non-Si transistor more expensive than the Si semiconductor element further rises. In the technology disclosed in International Patent Publication No. 2001-020757, driving signals for driving the main transistor and the auxiliary transistor are supplied independently from each other. Therefore, when the inverter device is configured, driving signals twice as many as normal driving signals are necessary. As a result, a driving control circuit cannot be configured using a general-purpose device and the price of the driving control circuit rises.
The present invention has been devised in view of the above and it is an object of the present invention to provide an inverter device that can realize a further reduction in costs while enjoying a loss reduction effect and an air conditioner including the inverter device.